
With a HINT of ammonia.
The Big Bang Theory Season 5, Episode 7

I'll give you a HINT.
The Big Bang Theory Season 1, Episode 6

Hint: it's based
on Sanskrit,
The Big Bang Theory Season 12, Episode 2

All right, give me a HINT.
The Big Bang Theory Season 7, Episode 7

Is "back on track" a HINT
that it has something to do with trains?
The Big Bang Theory Season 10, Episode 11